Topics on Continuous Training

V. Volo Bautista, D. Rodríguez Baeza

Dermatology Department. Río Hortega University Hospital. Valladolid

Abstract Psoriasis is a chronic inflammatory skin disease that may present during childhood, with a significant impact on the quality of life of both patients and their families. Its pathophysiology involves a genetic predisposition, the action of triggering factors, and an inflammatory response mainly mediated by the IL-23/IL-17 axis. Several clinical variants exist, but all share common features and may be associated with comorbidities such as obesity and psoriatic arthritis. Diagnosis is primarily clinical and requires accurate recognition of the differential diagnosis with other common papulosquamous disorders in childhood, including seborrheic dermatitis, tinea corporis, nummular eczema, pityriasis rubra pilaris, cutaneous T-cell lymphoma, and pityriasis rosea. Treatment should be individualized according to disease severity and includes topical therapies, phototherapy, non-biologic systemic treatments, and biological agents. An early and coordinated approach from primary care enables optimization of initial management and improves prognosis and quality of life in pediatric patients.

 

Resumen La psoriasis es una enfermedad inflamatoria crónica de la piel que puede debutar durante la infancia con un impacto significativo en la calidad de vida del paciente y su familia. Su fisiopatología implica una predisposición genética, la acción de factores desencadenantes y una respuesta inflamatoria mediada principalmente por el eje IL-23/IL-17. Existen diferentes variantes clínicas, pero todas comparten características comunes, pudiendo asociarse a comorbilidades como obesidad y artritis psoriásica. El diagnóstico es fundamentalmente clínico y requiere un adecuado reconocimiento del diagnóstico diferencial con otros trastornos papuloescamosos frecuentes en la infancia, como: dermatitis seborreica, tiña corporis, eccema numular, pitiriasis rubra pilaris, linfoma cutáneo de células T y pitiriasis rosada. El tratamiento debe individualizarse según la gravedad de la enfermedad e incluye terapias tópicas, fototerapia, tratamientos sistémicos no biológicos y fármacos biológicos. Un abordaje precoz y coordinado desde Atención Primaria permite optimizar el manejo inicial y mejorar el pronóstico y la calidad de vida de los pacientes pediátricos.

 

Key words: Psoriasis; Papulosquamous disorders; Pediatrics.

Palabras clave: Psoriasis; Trastornos papuloescamosos; Pediatría.

 

 

Pediatr Integral 2026; XXX (4): 248 – 254

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Papulosquamous disorders. Psoriasis

https://doi.org/10.63149/j.pedint.146

 

PSORIASIS

Introduction

It is a chronic inflammatory skin disease that has a major impact on the quality of life and development of children.

Psoriasis is an inflammatory disease with a chronic and relapsing course. It is a systemic disease in which up to 20-30% of patients have or will develop psoriatic arthritis. Although more characteristic of adults, it can appear at any age, including childhood. There is great clinical and evolutionary variability, and its proper identification in Primary Care (PC) allows for reducing diagnostic delays, avoiding inappropriate treatments, and improving the quality of life of patients and their families(1).

Epidemiology

One third of patients with psoriasis develop the disease in childhood.

Its distribution is universal and its prevalence varies between 1 and 3%, being more frequent in the Caucasian population. It is estimated that one-third of patients develop the disease during the first or second decade of life(2). The age of onset is earlier in women, although the natural course is similar: chronic with intermittent remissions.

Genetic involvement is demonstrated by its strong familial predisposition, as up to 40% of patients have a first-degree relative with the condition. Sixteen loci are known to be potentially responsible for the onset of psoriasis; nine of these have been designated PSORS 1-9 (from the English word psoriasis susceptibility)(3). The one most clearly associated with the disease is PSORS1, which contains the HLA-Cw6 allele, considered the best-known risk marker for disease development, early onset, and a more severe course.

Pathophysiology

Psoriasis occurs in genetically predisposed patients, in whom various environmental factors trigger immune dysregulation where the IL-23/IL-17 axis plays a central role.

Its cause is unknown. Several genetic factors, mentioned previously, contribute to the predisposition to the onset and development of the disease, and environmental triggering factors contribute to the first manifestation or exacerbations. Table I describes the best-known triggering factors.

 

Today, psoriasis is considered an inflammatory disease with an immune basis, dependent on the differentiation and proliferation of Th1 and Th17 lymphocytes(1-4). In its pathophysiology, damaged keratinocytes release signals that activate dendritic cells, which produce pro-inflammatory interleukins, such as IL-23. This IL-23 promotes the expansion and maintenance of Th17 lymphocytes, which, in turn, secrete IL-17, promoting keratinocyte proliferation and cutaneous inflammation. Simultaneously, Th1 cells contribute by producing IFN-γ, amplifying the inflammatory response. Thus, the interaction of this inflammatory loop constitutes a key axis in the perpetuation of inflammation and the epidermal hyperproliferation characteristic of psoriasis.

Clinical manifestations

Although there are several clinical variants, they all share common lesions in the form of well-defined papules or plaques with silvery scaling.

The lesions can affect the skin, nails, and, rarely, mucous membranes. Although they can vary in extent and size, all lesions usually share the same morphology: well-defined papules or plaques with erythema, thickening, and silvery scaling(5). Occasionally, pustules are present, as in generalized pustular psoriasis or palmoplantar pustulosis. Psoriasis manifests in different clinical variants that differ in their morphology, distribution, and evolution.

Plaque psoriasis

Also called psoriasis vulgaris. It is the most common form in both adults and children(6) and is characterized by a variable number of erythematous-squamous plaques on the elbows, knees, trunk, and lumbosacral region (Fig. 1).

Scalp involvement is frequent and, sometimes, the only manifestation of the disease, appearing as thick, adherent scales with well-defined borders (Fig. 2). Of the various instruments used to assess severity, the most widely used is the PASI (Psoriasis Area and Severity Index)(7). This index assesses the affected body surface area, erythema, scaling, and plaque thickness, and calculates a score from 0 to 72 based on severity and extent.

Guttate psoriasis

Guttate psoriasis is more common in children and adolescents. The plaques are small (usually less than 1 cm) and spread over the trunk (Fig. 3). Occasionally, it is the initial presentation of psoriasis following group A beta-hemolytic streptococcal pharyngitis. More than 50% of patients have high ASLO (antistreptolysin O) titers. It usually persists for 2–3 months, although some patients experience recurrent flares. In a significant percentage of patients, it can progress to chronic plaque psoriasis.

Erythrodermic psoriasis

It is a widespread form of psoriasis, affecting more than 80% of the body surface. The onset can be gradual, spreading from the typical lesions of psoriasis vulgaris, or sudden. It is a severe form that can lead to complications such as impaired thermoregulation, electrolyte imbalances, dehydration, and bacterial superinfections.

Nail psoriasis

It occurs in 20 to 40% of patients with psoriasis. Fingernails are more frequently affected than toenails. Findings in nail psoriasis include: pitting (pinpoint depressions of the nail plate, Fig. 4); oil spots; distal onycholysis (separation of the nail plate from the nail bed); subungual hyperkeratosis; and splinter hemorrhages. It is a risk marker for joint involvement.

Inverse psoriasis

It manifests as shiny erythematous plaques, with little scaling, in folds such as the armpits, genitocrural, submammary and intergluteal folds.

Pustular variants

• Pustular psoriasis: the generalized variant, also called Von Zumbusch psoriasis is an acute and rare form of psoriasis characterized by a sudden onset of widespread eruption with the formation of painful pustules.

• Palmoplantar pustulosis: characterized by the appearance of sterile pustules on the palms and soles over an erythematous base. Unlike the generalized variant, it progresses in the form of chronic and relapsing outbreaks.

Comorbidities

Pediatric psoriasis, as in adults, is a multisystemic disease, which in many cases is associated with various comorbidities, such as psoriatic arthritis, obesity or metabolic syndrome.

Psoriatic arthritis

Psoriatic arthropathy occurs in less than 6% of children with psoriasis. It can occur alongside the cutaneous manifestations of the disease. There are several patterns, including the asymmetric oligoarticular form, rheumatoid arthritis-like form, mutilating form, distal interphalangeal form, and predominantly axial arthritis(8).

Obesity and cardiovascular risk

Obesity is the most common comorbidity in pediatric psoriasis(9). Both children with severe and mild psoriasis have an increased risk of obesity. Furthermore, as in adults, there is an increased prevalence of metabolic syndrome, with higher rates of hyperlipidemia, hypertension, and diabetes.

Diagnosis

The diagnosis is primarily based on clinical assessment.

Psoriasis is primarily diagnosed through clinical assessment of skin lesions, their typical distribution, and the patient’s medical history. Dermatoscopy can be helpful in revealing regular punctate vessels on an erythematous background in psoriatic plaques. Biopsy is rarely required for diagnostic confirmation.

Differential diagnosis

The main differential diagnoses for psoriasis include other papulosquamous dermatoses.

As listed in table II, the differential diagnoses of psoriasis vulgaris include: seborrheic dermatitis, tinea corporis, nummular eczema, pityriasis rubra pilaris (PRP), cutaneous T-cell lymphoma (mycosis fungoides), and pityriasis rosea.

 

Treatment

The therapeutic approach to pediatric psoriasis is based on educating the patient and their family as well as individualizing treatment according to the extent of the disease and its impact on quality of life. Topical therapies, phototherapy, and systemic treatments, including biologics, are combined with the goal of achieving effective and sustained disease control while minimizing adverse effects.

Patients and their families should be educated about the chronic nature of the disease. Treatments should be individualized based on the extent of the case and its impact on the patient’s quality of life. Furthermore, physicians must be aware that, since there is no definitive cure, the toxicities caused by the various therapies must be minimized as much as possible.

Topical therapy

Topical corticosteroids

Currently, these medications are available in various formulations, such as ointments, creams, lotions, foams, and shampoos. The choice of formulation should be adapted to the anatomical location of the lesions: lotions, foams, or shampoos for the scalp; creams for skin folds and the face; and ointments for hyperkeratotic plaques. In clinical practice, medium- to high-potency corticosteroids, such as betamethasone dipropionate, are commonly used for limited periods of 2–4 weeks, especially in areas of thin or intertriginous skin. According to recent evidence, intermittent maintenance treatment on weekends is possible without adverse effects.

Vitamin D analogues

Its mechanism of action consists of inhibiting epidermal proliferation and inducing proper epidermal differentiation. The most commonly used molecule in Spain is calcipotriol. Its onset of action is delayed and its efficacy is limited, so it is usually used in combination with topical corticosteroids. A significant synergistic effect of both therapies has been demonstrated, and in routine clinical practice, the combination of topical corticosteroids and vitamin D analogues is the first-line treatment. This treatment is safe, effective, and relatively well-tolerated in children of all ages(9).

Calcineurin inhibitors

They are primarily used as an alternative to topical corticosteroid treatment in areas at higher risk of skin atrophy, such as the face, intertriginous areas, and genitals. They are applied twice daily. The most commonly used active ingredients are 0.1% tacrolimus ointment and 1% pimecrolimus cream.

Phototherapy

Pediatric patients with chronic plaque psoriasis who present with extensive disease, involvement of specific areas, significant impact on quality of life, and in whom topical treatments are ineffective, are candidates for systemic therapy and phototherapy. Likewise, the development of psoriatic arthritis is also an indication for treatment with conventional systemic and biologic therapies. These treatments are usually combined with topical therapy.

The most commonly used wavelength in pediatrics is narrowband ultraviolet B (UVB-Be) radiation. UVB-Be is considered an effective and safe treatment for patients with moderate to severe plaque or guttate psoriasis(6,10,11). The adverse effects of phototherapy in children are similar to those in adults. These include erythema, blistering, hyperpigmentation, pruritus, viral reactivation, and an increased risk of skin carcinogenesis with prolonged use.

Systemic therapies

Methotrexate

It is the most widely used non-biologic systemic treatment for moderate-to-severe plaque psoriasis in children(6,12). It allows for good medium- and long-term control, although it requires periodic laboratory monitoring. Its most frequent adverse effects are gastrointestinal and transient elevation of transaminases; serious complications are infrequent in children with adequate follow-up. It is also useful for the treatment of psoriatic arthritis.

Cyclosporine

It is a rapid-acting immunosuppressant, and its primary indication is the short-term control of generalized erythrodermic or pustular psoriasis. Prolonged use is not recommended due to its potential for nephrotoxicity and induction of hypertension.

Acitretin

Especially useful in the management of palmoplantar pustular psoriasis. It works by normalizing the differentiation and proliferation of keratinocytes. Its adverse effects include dry skin and mucous membranes and alterations in the lipid profile, therefore requiring monitoring. Its main drawback is its teratogenicity, which limits its use in adolescent girls.

Biological therapies

Biologics are immunomodulatory drugs that act on specific pathways of the immune system. Their use in children has increased due to their high efficacy and favorable safety profile; however, in addition to their high cost, they have other significant limitations, such as the need for thorough screening for chronic infectious diseases (especially tuberculosis, HIV, and hepatitis B and C), the need to update the vaccination schedule before starting treatment, and contraindications or precautions in patients with active infections(6,13). Table III lists the main biologic therapies for the treatment of moderate-to-severe plaque psoriasis in pediatric patients.

 

OTHER PAPULOSQUAMOUS DISORDERS IN PEDIATRICS

Lichen planus

Rare papulosquamous dermatosis in children, characterized by pruritic violaceous papules and possible involvement of the oral mucosa with whitish reticulation.

Lichen planus is a relatively common inflammatory disease that can affect the skin, mucous membranes, and nails, although its presentation in childhood is less common than in adults(14). Typical cutaneous manifestations consist of pruritic, polygonal, shiny papules with a flat surface and a purplish color (Fig. 5), with a characteristic distribution on the wrists, ankles, and sacral region. A suggestive clinical finding is the presence of fine whitish lines on the surface of the lesions, known as Wickham’s striae. Mucosal involvement can occur in isolation (15-25% of cases) or be associated with cutaneous lesions; the most common form is a whitish reticular pattern on the buccal mucosa, generally asymptomatic and with a chronic course. Diagnosis is primarily clinical. Initial treatment in primary care is based on high-potency topical corticosteroids, with a good response in most cases. Extensive involvement, symptomatic mucosal involvement, nail involvement, or lack of response to topical treatment justify referral to Dermatology for specialized evaluation.

Gilbert’s pityriasis rosea

Acute, self-limiting erythematous-desquamative eruption, typical of adolescents, which begins with a heraldic medallion, usually on the trunk, and progresses with smaller lesions.

This is an acute, self-limiting, erythematous-desquamative eruption that manifests primarily in adolescence. It frequently appears in spring and autumn, suggesting an infectious origin, likely related to human herpesviruses 6 and 7. It begins with a single lesion on the trunk, a 2-5 cm macule with peripheral desquamation, known as a herald medallion. It may coincide with the onset of flu-like symptoms, supporting the possible viral origin of the disease. Two to three days after the onset, similar, smaller lesions appear on the trunk and proximal extremities (Fig. 6). These lesions follow Langer’s lines (skin tension lines), creating the typical “Christmas tree” pattern on the back. Due to the asymptomatic and self-limiting nature of the condition, only reassurance is needed for family members and patients(15).

Pityriasis rubra pilaris (PRP)

A rare entity characterized by: hyperkeratotic papules that merge into large plaques leaving islands of healthy skin; and a typical, orange-colored palmoplantar keratoderma.

Palmoplantar keratoderma (PRP) is a rare disease of variable severity and uncertain etiology. There is a juvenile type, inherited in an autosomal dominant pattern, with onset between 5 and 10 years of age(16). Clinical findings are similar to those in adults, presenting as hyperkeratotic papules on the hands, trunk, elbows, and knees, which tend to coalesce into large plaques, but typically leave islands of healthy skin. A characteristic orange-yellow palmoplantar keratoderma also appears. The disease is very difficult to treat, requiring specialized management with systemic retinoids or biologic drugs.

Role of the Primary Care Pediatrician

The pediatrician plays a key role in the early diagnosis and initial management of childhood psoriasis, especially in mild forms, which can be effectively treated at this level of care. It is important to recognize the different clinical subtypes and, in the case of guttate psoriasis, to consider performing a throat culture or ASLO titration to rule out a triggering streptococcal infection. The pediatrician should maintain a high index of suspicion for psoriatic arthritis, conducting a focused medical history and a thorough physical examination, and recognizing associated risk factors, such as nail involvement, which may precede or accompany joint involvement. It is essential to identify frequently associated comorbidities, such as obesity and metabolic syndrome, which should be managed in primary care. It is important to know and be able to identify the most common presentations in the differential diagnosis of childhood psoriasis in order to avoid diagnostic delays and inappropriate treatments.

It is essential to know the referral criteria for children with psoriasis to Dermatology, which include:

• Affecting more than 3% of the body surface.

• Presence of arthritis.

• Lack of response to topical treatments.

• Diagnostic uncertainty.

 

Conflict of interest

There is no conflict of interest in the preparation of this manuscript nor any source of funding.

 

References

The asterisks indicate the article’s level of interest, in the authors’ opinion.

1. Silverberg NB. Pediatric psoriasis: an update. Ther Clin Risk Manag. 2009; 5: 849-56. Available in: https://doi.org/10.2147/tcrm.s4908.

2. Dogra S, Kaur I. Childhood psoriasis. Indian J Dermatol Venereol Leprol. 2010; 76: 357-65. Available in: https://doi.org/10.4103/0378-6323.66580.

3. Bowcock AM, Krueger JG. Getting under the skin: the immunogenetics of psoriasis. Nat Rev Immunol. 2005; 5: 699-711. Available in: https://doi.org/10.1038/nri1689.

4. Nestle FO, Kaplan DH, Barker J. Psoriasis. N Engl J Med. 2009; 361: 496-509. Available in: https://doi.org/10.1056/NEJMra0804595.

5. Van de Kerkhof PCM, Nestle FO. Psoriasis. In: Bolognia JL, Schaffer JV, Cerroni L, eds. Dermatology. Barcelona: Elsevier Ltd.; 2018. p. 138-60.

6.*** Vicente A, Pérez-Ferriols A, Batalla A, García-Fernández L, Pérez B, Eiris N, et al. Consensus Statement from the Spanish Academy of Dermatology and Venereology (AEDV) Psoriasis Working Group (SWG) and Pediatric Working Group (PWG) on the Management of Pediatric Psoriasis. Actas Dermosifiliogr. 2025; 116: 254-80. Available in: https://doi.org/10.1016/j.ad.2024.12.015.

7. Schmitt J, Wozel G. The psoriasis area and severity index is the adequate criterion to define severity in chronic plaque-type psoriasis. Dermatology. 2005; 210: 194-9. Available in: https://doi.org/10.1159/000083509.

8. Zisman D, Gladman DD, Stoll ML, Stand V, Lavi I, Hsu JJ, Mellins ED, et al. The Juvenile Psoriatic Arthritis Cohort in the CARRA Registry: Clinical Characteristics, Classification, and Outcomes. J Rheumatol. 2017; 44: 342-51. Available in: https://doi.org/10.3899/jrheum.160717.

9. Paller AS, Mercy K, Kwasny MJ, Choon SE, Cordoro KM, Girolomoni G, et al. Association of pediatric psoriasis severity with excess and central adiposity: an international cross-sectional study. JAMA Dermatol. 2013; 149: 166-76. Available in: https://doi.org/10.1001/jamadermatol.2013.1078.

10.*** Menter A, Cordoro KM, Davis DMR, Kroshinsky D, Paller AS, Armstrong AW, et al. Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis in pediatric patients. J Am Acad Dermatol. 2020; 82: 161-201. Available in: https://doi.org/10.1016/j.jaad.2019.08.049.

11. Pavlovsky M, Baum S, Shpiro D, Pavlovsky L, Pavlotsky F. Narrow band UVB: is it effective and safe for pediatric psoriasis and atopic dermatitis? J Eur Acad Dermatol Venereol. 2011; 25: 727-9. Available in: https://doi.org/10.1111/j.1468-3083.2010.03832.x.

12.* Menter A, Gelfand JM, Connor C, Armstrong AW, Cordoro KM, Davis DMR, et al. Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management of psoriasis with systemic nonbiologic therapies. J Am Acad Dermatol. 2020; 82: 1445-86. Available in: https://doi.org/10.1016/j.jaad.2020.02.044.

13.* Menter A, Strober BE, Kaplan DH, Kivelevitch D, Prater EF, Stoff B, et al. Joint AAD-NPF guidelines of care for the management and treatment of psoriasis with biologics. J Am Acad Dermatol. 2019; 80: 1029-72. Available in: https://doi.org/10.1016/j.jaad.2018.11.057.

14. Le Cleach L, Chosidow O. Clinical practice. Lichen planus. N Engl J Med. 2012; 366: 723-32. Available in: https://doi.org/10.1056/NEJMcp1103641.

15. Moreno Ramírez D. Dermatosis eritematoescamosas. Erythematous-squamous Dermatosis. In: Bielsa I, ed. Dermatología clínica. Barcelona: Elsevier España; 2019. p. 156-76.

16. Yang CC, Shih IH, Lin WL, Yu YS, Chiu HC, Huang PH, et al. Juvenile pityriasis rubra pilaris: report of 28 cases in Taiwan. J Am Acad Dermatol. 2008; 59: 943-8. Available in: https://doi.org/10.1016/j.jaad.2008.07.054.

17. Quintana Castanedo L, de Lucas Laguna R. Psoriasis y otros trastornos papuloescamosos. Pediatr Psoriasis and other papulosquamous disorders. Pediatr Integral. 2021; 4: 177-83. Available in: https://www.pediatriaintegral.es/publicacion-2021-06/psoriasis-y-otros-trastornos-papuloescamosos/.

 

Recommended bibliography

– Vicente A, Pérez-Ferriols A, Batalla A, García-Fernández L, Pérez B, Eiris N, et al. Consensus Statement from the Spanish Academy of Dermatology and Venereology (AEDV) Psoriasis Working Group (SWG) and Pediatric Working Group (PWG) on the Management of Pediatric Psoriasis. Actas Dermosifiliogr. 2025; 116: 254-80. Available in: https://doi.org/10.1016/j.ad.2024.12.015.

Open access article. The Psoriasis and Pediatric Dermatology Groups (GPS and GEDP) of the Spanish Academy of Dermatology and Venereology (AEDV) provide their recommendations for the treatment of pediatric psoriasis, based on the best available evidence and expert experience.

– Menter A, Cordoro KM, Davis DMR, Kroshinsky D, Paller AS, Armstrong AW, et al. Joint American Academy of Dermatology-National Psoriasis Foundation guidelines of care for the management and treatment of psoriasis in pediatric patients. J Am Acad Dermatol. 2020; 82: 161-201. Available in: https://doi.org/10.1016/j.jaad.2019.08.049.

Clinical guidelines from the American Academy of Dermatology reviewing the latest evidence on pediatric psoriasis. They also establish treatment guidelines based on the specific characteristics of psoriasis in children.

 

Clinical case

A 9-year-old girl, with no relevant medical history, presented with progressive appearance of skin lesions over the past two weeks. She did not report itching. There was no known family history of psoriasis. The lesions initially appeared on her trunk and had rapidly spread to her abdomen and proximal extremities. During the medical history interview, the patient reported having had a fever and sore throat one month prior. On examination, she appeared in good general condition with multiple well-defined, erythematous-squamous papules and small plaques diffusely distributed over her trunk and proximal extremities (Fig. 7). Figure 7.